is my lens crappy or is it me?

kkamin · Nov 24, 2009

Hello,

I'm shooting with a Canon xsi with the standard 18-55mm EF-S lens that frequently comes with it. I've been shooting with strobes at 1/125th at F/8, 200 ISO. The problem is that some of my shots are not very sharp.

The strobe is firing very fast (I think somewhere between 1/800th sec to 1/2000th sec). There is almost no ambient light in the studio. SHouldn't the strobe freeze the action, almost no matter what?

Could it be the lens itself does not have the best optics? How much improvement would I notice if I went to a 70mm prime? Is there anything decent I can buy for $200?

Thanks, everyone.

Kkamin

Derrel · Nov 24, 2009

I have the Canon EF 18-55 kit zoom, the non-IS one, the early USA version, not the Japan-market one with the ultrasonic motor. The lens performs absolutely craptastically--lots of color fringing, bad edge performance, just an all-around subpar lens design. Very weak optical performance,even fairly well stopped-down. Apparently, the later, Image Stabilizer version is a better lens.

70mm brings to mind the Sigma 70mm macro lens, which is a really good lens from everything I've seen shot by it. It would be easy to find a cheap,modern zoom lens that would perform better than the first-version 18-55.

grafxman · Nov 24, 2009

kkamin said:
Hello,

I'm shooting with a Canon xsi with the standard 18-55mm EOS lens that frequently comes with it. I've been shooting with strobes at 1/125th at F/8, 200 ISO. The problem is that some of my shots are not very sharp.

The strobe is firing very fast (I think somewhere between 1/800th sec to 1/2000th sec). There is almost no ambient light in the studio. SHouldn't the strobe freeze the action, almost no matter what?

Could it be the lens itself does not have the best optics? How much improvement would I notice if I went to a 70mm prime? Is there anything decent I can buy for $200?

Thanks, everyone.

Kkamin

A prime will usually have better optics than a zoom. Before you go purchase another lens perhaps you should check your lens' sharpness using the technique described here:

AF microadjustment for the 1Ds mark III, 1D Mk3, 5D Mk2, 7D

That procedure will tell you about your lens' sharpness as well as how to correct an out of focus condition.

Alternatively you could tape up a newspaper page 15 feet or so away, mount the camera on a tripod, manually focus using a magnified live view, then switch to automatic focus, press the shutter release and see if the focus ring moves. The lens should be wide open using this procedure so there is no depth of field. If the focus ring moves, you MAY have a problem that you need to correct with a camera adjustment. Try the procedure at various zoom settings. Hope this helps. Good luck.

Big Mike · Nov 25, 2009

Unfortunately, the XSi doesn't have micro focus adjust. (not that I know of, anyway).
You can still do some fairly simple tests to check the focus accuracy.

It would help if you could post up some examples. It may or may not be a 'poor lens' issue...and it may or may not be a focus issue.

I've also got the old 'crappy' 18-55mm lens. It's not as bad as most people make it out to be...but I haven't used mine in several years because I have better lenses in my bag.

Is there anything decent I can buy for $200?

The EF 50mm F1.8 is Canon's least expensive lens. It's 'cheap' and has many plastic parts...but the glass is pretty decent.

Village Idiot · Nov 25, 2009

I've gotten some great shots with the good ol' 18-55. With the IS version stopped down in controlled conditions in a studio, it shouldn't be too bad.

The Lincoln Monument on Flickr - Photo Sharing!
The Washington Monument on Flickr - Photo Sharing!
Where Does the Light Go? on Flickr - Photo Sharing!
Control Room on Flickr - Photo Sharing!

IgsEMT · Nov 25, 2009

Is there anything decent I can buy for $200?

Look into used equipment from reliable dealer. My main glass in used, no VR but its quality is AMAZING (and I'm being objective here).

Derrel · Nov 25, 2009

Look at this review and you'll see how the original 18-55 performed in the hands of an avid Canon tester, Bob Atkins. He has lots of other practical tests of Canon lenses on his pages,so you ought to be able to find one that looks good and is within your budget.

Canon EF-S 18-55mm f/3.5-5.6 Lens Review - the Rebel and Rebel XT Kit Lens - photo.net

ZBob · Nov 25, 2009

It's crappy. Try the 50mm 1.8 II. It's really cheap and very sharp.

cfusionpm · Nov 25, 2009

Derrel said:
Look at this review and you'll see how the original 18-55 performed in the hands of an avid Canon tester, Bob Atkins. He has lots of other practical tests of Canon lenses on his pages,so you ought to be able to find one that looks good and is within your budget.

Canon EF-S 18-55mm f/3.5-5.6 Lens Review - the Rebel and Rebel XT Kit Lens - photo.net

That's cool and all, but that's not the lens the OP has. This is: http://the-digital-picture.com/Reviews/Canon-EF-S-18-55mm-f-3.5-5.6-IS-Lens-Review.aspx

Though, he does have some nice things to say about the "L-class image quality" 17-55mm 2.8 lens.

kkamin · Nov 26, 2009

Big Mike said:
It would help if you could post up some examples. It may or may not be a 'poor lens' issue...and it may or may not be a focus issue.

Here is the image. It looks fairly sharp at 100% magnification (cropped down to about seventy percent of its original size), but when I zoom in, all the girl's faces are like the one I isolated. Maybe I am expecting too much from the lens, but I would think it would be sharper than that. (The close up of girl's face is at 100% magnification, it hasn't been resized).

And again, I am shooting with strobes and my camera is at a 1/200th sec. , ISO 200, f/8

Derrel · Nov 26, 2009

Yup, that's what a crummy optical performance looks like. She's in focus--this is not a case of mis-focusing or being outside the depth of field band. That's just bad optics. And what a shame too--the photo is simple and well-lighted. One would expect that at f/8 a lens would be good. Your work deserves better.

grafxman · Nov 26, 2009

Derrel said:
Yup, that's what a crummy optical performance looks like. She's in focus--this is not a case of mis-focusing or being outside the depth of field band. That's just bad optics. And what a shame too--the photo is simple and well-lighted. One would expect that at f/8 a lens would be good. Your work deserves better.

You're probably right. F8 should have everything in focus. However, to my old eyes, that collar area looks razor sharp to me. I zoomed in to 200% with my Opera browser and it still looks sharp.

I reiterate what I stated in a previous post, the lens should be opened wide with the camera on a tripod. It should be manually focused onto a newspaper mounted 15 feet or so away using the magnified life view. It should then be placed to auto focus and the shutter release pressed while watching the focus ring. If it moves then you have a focus problem, not necessarily a bad lens. The focus problem may possibly be corrected within the camera or by sending it to Canon. It's a simple test that can be easily accomplished within 30 minutes or less.

kkamin · Nov 26, 2009

grafxman said:
Derrel said:

However, to my old eyes, that collar area looks razor sharp to me. I zoomed in to 200% with my Opera browser and it still looks sharp.

I reiterate what I stated in a previous post, the lens should be opened wide with the camera on a tripod. It should be manually focused onto a newspaper mounted 15 feet or so away using the magnified life view. It should then be placed to auto focus and the shutter release pressed while watching the focus ring. If it moves then you have a focus problem, not necessarily a bad lens. The focus problem may possibly be corrected within the camera or by sending it to Canon. It's a simple test that can be easily accomplished within 30 minutes or less.

Click to expand...

The collar does look sharp, but I think it's the simple nature of that shape at that focal point, with my lens. If that was the target of my focus there is no reason that the face behind would not share that. The flash is firing quickly at f/8, probably somewhere at 1/1000 a sec. It should freeze pretty much anything in acceptable focus.

I did some quick focus tests following your methodology and my lens' are accurate; there was little or no movement when I focused the target. and switched from manual to auto focus.

So my conclusion is that the kit lens for the xsi is decent and affordable but not up to standards for someone charging people money. Ironically I am purchasing the Canon EF 1.8 to get a sharper image and greater depth of field for portraits, but I already have accepted that the lens is a stepping stone to the 1.4.

Derrel · Nov 27, 2009

You know, this page right here Canon EF-S 18-55mm f/3.5-5.6 IS Lens Review

has a mouse-oer that shows the craptastic image performance of the 18-55 IS--the one sold with a zillion XSi's. The *original* 18-55, the first US model, was absolutely plagued with chromatic aberration. I looked briefly at the dPreview "review" of the 18-55 IS, and they softballed it.

Look at this review,and do the mouse-over, and you will see what I see,and waht many discerning lens afficionados see--LOADS of chromatic aberration that ruins the pictures with an all-over sort of color blur. It's "well-corrected" chromatic aberration, meaning it does not have big, honking, easily-seen fringes of color. But there is an overall "color blur" as one reviewer describes it.

Please compare the Canon 18-55 IS lens with their 17-55 lens at the above mouse-ovr link, and you an see that the difference in the Chromatic Aberration control of the 17-55 is clearly and instantly visible. Look at kkamin's shot--the woman's eyebrow is "almost" resolved, but not quite. The shot he is showing us in *in-focus*. These dPreview softball reviews calling the 18-55's performance "good" in words, but then giving the lens a 7.5 on image quality is ridiculous. No offense, but the 18-55 IS kit lens was computed for 6 to 8.2 megapixel sensors; the XSi has a very densely packed 12.2 megapixel sensor. Off of the center, at f/5.6, the 18-55 is plagued by chromatic aberration,especially at f/5.6.

The bottom line: this lens was FINE on the 8.2 megapixel bodies from several years ago, but this lens is simply NOT good enough for a 12.2 MP sensor. When this lens was tested on the old 350D, it looked good...that was years ago. The 12.2 MP cameras like Rebels XSi and Nikon D2x have small, high-density sensors and they demand top-quality lenses to work well. On the new 7D, with 18 megapixels, I don't think even the 17-55 f/2.8 is good enough at the wide end to shine on that particular sensor...and the kit lens looks like garbage on the 7D. The 28-55 IS lens was never meant to be used on a small,high-density sensor--it's from another "era". Just look at the mouse-over and see: the 18-55 sample there looks just like kkamin's picture does--a vague, general resolution of finer detail, but not the real crystal clarity that the 17-55 delivers. The "well-controlled" chromatic aberration is not obvious--but it subtly ruins many,many images.